Ask Xulfiqar - An Automotive Encyclopedia

[Xulfiqar]

the IGF wire comes out from ignitor and goes directly to the ECU, it tells the ECU that ignitor fired the coil and an ignition event occured Your engine will not run with it disconnected. DO not wire the black rpm wire to the ECU, its too noisy.

The coil has two wires, one is thicker and has a stripe - one is thinner and is solid black, the thicker one is power from the ignition switch or main relay, the thinner one is the negative wire and drives the rpm meter, it also is branched into the diagnosis port but it never goes to any pin in the ECU.

ergo IG- and IGF are not the same.

IG- = rpm
IGT = ignition trigger
IGF = ignition feedback

[saadeez101]

the IGF wire comes out from ignitor and goes directly to the ECU, it tells the ECU that ignitor fired the coil and an ignition event occured Your engine will not run with it disconnected. DO not wire the black rpm wire to the ECU, its too noisy.

The coil has two wires, one is thicker and has a stripe - one is thinner and is solid black, the thicker one is power from the ignition switch or main relay, the thinner one is the negative wire and drives the rpm meter, it also is branched into the diagnosis port but it never goes to any pin in the ECU.

ergo IG- and IGF are not the same.

IG- = rpm
IGT = ignition trigger
IGF = ignition feedback

merci monsieur, i didn't connected black wire to ecu , but i am curious that which wire from ECU can drive RPM then.
funny thing is, the leftover thin black wire is somehow getting ground, cuz when check it with multimeter, it was showing some reading

[Xulfiqar]

merci monsieur, i didn't connected black wire to ecu , but i am curious that which wire from ECU can drive RPM then.
funny thing is, the leftover thin black wire is somehow getting ground, cuz when check it with multimeter, it was showing some reading

The ECU has no pin that can drive the rpm - in original form the thin black wire from the coil drives the rpm meter. You can find the wire near the ECU wiring harness where it becomes the body harness.

[Kiki091]

@xulfiqar bhai, now almost all the problems are sorted except the smoke issues. My CDI starts well when cold, the engine starts hunting fr a minute or less, then fine, then it gives out smoke on acceleration. The EGR is clean, manifold, injectors were installed brand new abt 30k kms back, brand new boost pressure sensor.. Please help in this regard..

[Kiki091]

@xulfiqar bhai, now almost all the problems are sorted except the smoke issues. My CDI starts well when cold, the engine starts hunting fr a minute or less, then fine, then it gives out smoke on acceleration. The EGR is clean, manifold, injectors were installed brand new abt 30k kms back, brand new boost pressure sensor.. Please help in this regard..

Can turbo be the cause?? Cause I believe my intercooler is full of oil, and the mechanics here refuse to clean it saying that it will increase the issue..

[Xulfiqar]

the mechanics are not opening it because they dont know how to open the clips and then wouldnt have the foggiest idea how to clean it, it requires a very good cleaning, for smoke, what are the injector run test results and what does the rail pressure sensor read (MB specific diagnosis unit can read that)

how old is your MAF sensor and what is the air intake look like on the diagnosis system.

[Kiki091]

the mechanics are not opening it because they dont know how to open the clips and then wouldnt have the foggiest idea how to clean it, it requires a very good cleaning, for smoke, what are the injector run test results and what does the rail pressure sensor read (MB specific diagnosis unit can read that)

how old is your MAF sensor and what is the air intake look like on the diagnosis system.

MAF is i believe 2 years/ 40k kms old. My mechanic says that my car has compression leak so the smoke wont go unless i get an overhaul... another thing is when the car is standing still no smoke, but as soon as the AC fan turns on it starts giving out smoke even on stand still with a weird smell.. and i will get the car cheked on the software again and will share the reaults with u..and what about the hunting on cold start??

[syncview]

was it compression tested?

[Kiki091]

was it compression tested?

No no it wasn't. He says its giving out blow by, when I checked it the oil cap was just juggling at one place plus the engine was overhauled about 40,000 kms back by the previous owner.

[margallar]

zulfiqar bhai. can an arcing coil also damage the ht lead connected to it? because the new lead i connected to it is arcing.

can it cause rough running if the lead is arcing with the cng kit, the car is jerking on cng

the coil's two nuts send sparks (thin, hard to see) to the centre, i have tried wrapping that area with tape but that didn't help.

[Xulfiqar]

No no it wasn't. He says its giving out blow by, when I checked it the oil cap was just juggling at one place plus the engine was overhauled about 40,000 kms back by the previous owner.

so your mechanic believes that a mercedes benz diesel has a service life of 40,000 kms? or was the previous owner a bit loopy when he handed the car over for overhaul.

in diesel engines - the blowby is highly dependant on injection timing too - one slight off beat and the blowby increases.

and btw - can you ask the previous owner what was done in the overhaul? if he says anything like new sleeves etc. then you already know whats up. If you smell the acrid stench of diesel exhaust (bitter) - your injection system is not upto par, something is causing it to go astray - your dashboard wont have a check light either and the only way to properly diagnose it is with an SDS and pull all the pending faults - Im pretty sure you will see the MAF as problematic.

The reason I say MAF is that the replacement item is only sold by Mercedes Benz, other MAFs from opels, VW and other Bosch part nos. look exactly similar but do not work (I have experienced that dozens of times - where owners bought a MAF sensor because it looks similar)

btw - when your mechanic says its leaking compression - ask him where is the compression going? A good mechanic will do a compression test on your engine. Its not that hard to pull the CDI injectors if one has the slide hammer puller for them - If not then mechanics in Pakistan usually break the injectors.

[Xulfiqar]

zulfiqar bhai. can an arcing coil also damage the ht lead connected to it? because the new lead i connected to it is arcing.

can it cause rough running if the lead is arcing with the cng kit, the car is jerking on cng

the coil's two nuts send sparks (thin, hard to see) to the centre, i have tried wrapping that area with tape but that didn't help.

the lead will be damaged in no time, you should apply some silicone grease to supress that spark - thats why its called dielectric grease.

[margallar]

the lead passes by the cng kit, touching it at one place, i see a blue glow there, i made a pretty fat sleeve for it using insulating tape, but still the spark gets through, the wire doesn't look like the insulation is bad, but i see carbon where there is that blue glow, is the cable done for? or can it be saved?

[Xulfiqar]

that cable is leaking. is the coil not original?

[margallar]

that cable is leaking. is the coil not original?

umm...sadly the coil is original :D...the cable was the best quality i could get, it was not leaking when i installed it a few months back, i feel somehow the arcing at the coil damaged it.

i feel that the sparks at the coil end are passing through the coil's own plastic body, though i can not be sure unless i use di electric grease in the wire's boot. they are so thin that i can't see where they end.

the sparks reduce in frequency when engine rpm increases

and there is white ash in the coil's socket AGAIN where the ht lead plugs in, i cleaned that too when i had replaced the wires, i used vaseline there and also on the nuts

i have some good cables, just need to cut them and install new connectors. but i don't think new wires would be a good idea without a new coil.

shitzuki dealers are asking insane amounts for even the new style coils

[ss_rebel]

Anyone ?

:-!

Xulfiqar bhai,

need ur help pls....

[I][I]@Xulfiqar

I have an issue .... the pick & more importantly, the mileage im getting from my City Prosmatec 2010 is...very sad.[/I]

after oil change (Caltex Havolin 10w30) & AC service (for diff reason thou) I'm not getting any better mileage. its around 9.4 km/l as per ODO.

previously, I've changed the plugs but they werent new. do u recommend that after getting totally new Honda spark plugs, it will return to normal which is around 12~14 km/l for City ?

or anything else still needs to be done? i read sumwhere on forum abt iridium plugs ? does Honda have those or have to buy them from sumwhere else ? will they be helpful ?

ur advise is really appreciated.

thanks.[/I]

[margallar]

Retested with another cable, arcing still there, mostly at the coil. It looks like those bug zapper machines sometimes. Car is grounded now, shops closed for eid,

I will get a carby cultus coil this time, the new plastic body one.

Nearby parts shop had new era coil, I will try to get new denso from dealer

I think I should improve engine ground too

Already replaced dizzy cap, rotor and wires

[StrikerX]

Anyone ?

:-!

City comes with OEM Iridium NGK's... They should last you 100k KM's easily.

[umarkhan1]

@xulfiqar bhai EID Mubarak to you
just for general knowledge,how does suction doors works in the mercedes S class???

[Xulfiqar]

@Xulfiqar bhai EID Mubarak to you
just for general knowledge,how does suction doors works in the mercedes S class???

Eid mubarak to you too.

The old S class W140 door close assist is a pretty neat system, it utilises a high pressure pump that "pushes" air through plastic lines which end in a working piston which in turn are connected to arms that are levered, so the push becomes pull for the doors, once the door latch is contacted the pump is commanded to release, it then applies a suction to the line to release the piston.

It has 4 dedicated circuits for the doors but one pump. Honestly the W140 was way ahead of its time - its downright amazing even 20 years later.